lib/CodeGen/MachineFunction.cpp

   1 //===- MachineFunction.cpp ------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Collect native machine code information for a function.  This allows
  10 // target-specific information about the generated code to be stored with each
  11 // function.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/CodeGen/MachineFunction.h"
  16 #include "llvm/ADT/BitVector.h"
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/ADT/DenseSet.h"
  19 #include "llvm/ADT/STLExtras.h"
  20 #include "llvm/ADT/SmallString.h"
  21 #include "llvm/ADT/SmallVector.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/ADT/Twine.h"
  24 #include "llvm/Analysis/ConstantFolding.h"
  25 #include "llvm/Analysis/EHPersonalities.h"
  26 #include "llvm/CodeGen/MachineBasicBlock.h"
  27 #include "llvm/CodeGen/MachineConstantPool.h"
  28 #include "llvm/CodeGen/MachineFrameInfo.h"
  29 #include "llvm/CodeGen/MachineInstr.h"
  30 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  31 #include "llvm/CodeGen/MachineMemOperand.h"
  32 #include "llvm/CodeGen/MachineModuleInfo.h"
  33 #include "llvm/CodeGen/MachineRegisterInfo.h"
  34 #include "llvm/CodeGen/PseudoSourceValue.h"
  35 #include "llvm/CodeGen/TargetFrameLowering.h"
  36 #include "llvm/CodeGen/TargetLowering.h"
  37 #include "llvm/CodeGen/TargetRegisterInfo.h"
  38 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  39 #include "llvm/CodeGen/WasmEHFuncInfo.h"
  40 #include "llvm/CodeGen/WinEHFuncInfo.h"
  41 #include "llvm/Config/llvm-config.h"
  42 #include "llvm/IR/Attributes.h"
  43 #include "llvm/IR/BasicBlock.h"
  44 #include "llvm/IR/Constant.h"
  45 #include "llvm/IR/DataLayout.h"
  46 #include "llvm/IR/DebugInfoMetadata.h"
  47 #include "llvm/IR/DerivedTypes.h"
  48 #include "llvm/IR/Function.h"
  49 #include "llvm/IR/GlobalValue.h"
  50 #include "llvm/IR/Instruction.h"
  51 #include "llvm/IR/Instructions.h"
  52 #include "llvm/IR/Metadata.h"
  53 #include "llvm/IR/Module.h"
  54 #include "llvm/IR/ModuleSlotTracker.h"
  55 #include "llvm/IR/Value.h"
  56 #include "llvm/MC/MCContext.h"
  57 #include "llvm/MC/MCSymbol.h"
  58 #include "llvm/MC/SectionKind.h"
  59 #include "llvm/Support/Casting.h"
  60 #include "llvm/Support/CommandLine.h"
  61 #include "llvm/Support/Compiler.h"
  62 #include "llvm/Support/DOTGraphTraits.h"
  63 #include "llvm/Support/Debug.h"
  64 #include "llvm/Support/ErrorHandling.h"
  65 #include "llvm/Support/GraphWriter.h"
  66 #include "llvm/Support/raw_ostream.h"
  67 #include "llvm/Target/TargetMachine.h"
  68 #include <algorithm>
  69 #include <cassert>
  70 #include <cstddef>
  71 #include <cstdint>
  72 #include <iterator>
  73 #include <string>
  74 #include <utility>
  75 #include <vector>
  76
  77 using namespace llvm;
  78
  79 #define DEBUG_TYPE "codegen"
  80
  81 static cl::opt<unsigned>
  82 AlignAllFunctions("align-all-functions",
  83                   cl::desc("Force the alignment of all functions."),
  84                   cl::init(0), cl::Hidden);
  85
  86 static const char *getPropertyName(MachineFunctionProperties::Property Prop) {
  87   using P = MachineFunctionProperties::Property;
  88
  89   switch(Prop) {
  90   case P::FailedISel: return "FailedISel";
  91   case P::IsSSA: return "IsSSA";
  92   case P::Legalized: return "Legalized";
  93   case P::NoPHIs: return "NoPHIs";
  94   case P::NoVRegs: return "NoVRegs";
  95   case P::RegBankSelected: return "RegBankSelected";
  96   case P::Selected: return "Selected";
  97   case P::TracksLiveness: return "TracksLiveness";
  98   }
  99   llvm_unreachable("Invalid machine function property");
 100 }
 101
 102 // Pin the vtable to this file.
 103 void MachineFunction::Delegate::anchor() {}
 104
 105 void MachineFunctionProperties::print(raw_ostream &OS) const {
 106   const char *Separator = "";
 107   for (BitVector::size_type I = 0; I < Properties.size(); ++I) {
 108     if (!Properties[I])
 109       continue;
 110     OS << Separator << getPropertyName(static_cast<Property>(I));
 111     Separator = ", ";
 112   }
 113 }
 114
 115 //===----------------------------------------------------------------------===//
 116 // MachineFunction implementation
 117 //===----------------------------------------------------------------------===//
 118
 119 // Out-of-line virtual method.
 120 MachineFunctionInfo::~MachineFunctionInfo() = default;
 121
 122 void ilist_alloc_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
 123   MBB->getParent()->DeleteMachineBasicBlock(MBB);
 124 }
 125
 126 static inline unsigned getFnStackAlignment(const TargetSubtargetInfo *STI,
 127                                            const Function &F) {
 128   if (F.hasFnAttribute(Attribute::StackAlignment))
 129     return F.getFnStackAlignment();
 130   return STI->getFrameLowering()->getStackAlignment();
 131 }
 132
 133 MachineFunction::MachineFunction(const Function &F,
 134                                  const LLVMTargetMachine &Target,
 135                                  const TargetSubtargetInfo &STI,
 136                                  unsigned FunctionNum, MachineModuleInfo &mmi)
 137     : F(F), Target(Target), STI(&STI), Ctx(mmi.getContext()), MMI(mmi) {
 138   FunctionNumber = FunctionNum;
 139   init();
 140 }
 141
 142 void MachineFunction::handleInsertion(MachineInstr &MI) {
 143   if (TheDelegate)
 144     TheDelegate->MF_HandleInsertion(MI);
 145 }
 146
 147 void MachineFunction::handleRemoval(MachineInstr &MI) {
 148   if (TheDelegate)
 149     TheDelegate->MF_HandleRemoval(MI);
 150 }
 151
 152 void MachineFunction::init() {
 153   // Assume the function starts in SSA form with correct liveness.
 154   Properties.set(MachineFunctionProperties::Property::IsSSA);
 155   Properties.set(MachineFunctionProperties::Property::TracksLiveness);
 156   if (STI->getRegisterInfo())
 157     RegInfo = new (Allocator) MachineRegisterInfo(this);
 158   else
 159     RegInfo = nullptr;
 160
 161   MFInfo = nullptr;
 162   // We can realign the stack if the target supports it and the user hasn't
 163   // explicitly asked us not to.
 164   bool CanRealignSP = STI->getFrameLowering()->isStackRealignable() &&
 165                       !F.hasFnAttribute("no-realign-stack");
 166   FrameInfo = new (Allocator) MachineFrameInfo(
 167       getFnStackAlignment(STI, F), /*StackRealignable=*/CanRealignSP,
 168       /*ForceRealign=*/CanRealignSP &&
 169           F.hasFnAttribute(Attribute::StackAlignment));
 170
 171   if (F.hasFnAttribute(Attribute::StackAlignment))
 172     FrameInfo->ensureMaxAlignment(F.getFnStackAlignment());
 173
 174   ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
 175   Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
 176
 177   // FIXME: Shouldn't use pref alignment if explicit alignment is set on F.
 178   // FIXME: Use Function::hasOptSize().
 179   if (!F.hasFnAttribute(Attribute::OptimizeForSize))
 180     Alignment = std::max(Alignment,
 181                          STI->getTargetLowering()->getPrefFunctionAlignment());
 182
 183   if (AlignAllFunctions)
 184     Alignment = AlignAllFunctions;
 185
 186   JumpTableInfo = nullptr;
 187
 188   if (isFuncletEHPersonality(classifyEHPersonality(
 189           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 190     WinEHInfo = new (Allocator) WinEHFuncInfo();
 191   }
 192
 193   if (isScopedEHPersonality(classifyEHPersonality(
 194           F.hasPersonalityFn() ? F.getPersonalityFn() : nullptr))) {
 195     WasmEHInfo = new (Allocator) WasmEHFuncInfo();
 196   }
 197
 198   assert(Target.isCompatibleDataLayout(getDataLayout()) &&
 199          "Can't create a MachineFunction using a Module with a "
 200          "Target-incompatible DataLayout attached\n");
 201
 202   PSVManager =
 203     llvm::make_unique<PseudoSourceValueManager>(*(getSubtarget().
 204                                                   getInstrInfo()));
 205 }
 206
 207 MachineFunction::~MachineFunction() {
 208   clear();
 209 }
 210
 211 void MachineFunction::clear() {
 212   Properties.reset();
 213   // Don't call destructors on MachineInstr and MachineOperand. All of their
 214   // memory comes from the BumpPtrAllocator which is about to be purged.
 215   //
 216   // Do call MachineBasicBlock destructors, it contains std::vectors.
 217   for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
 218     I->Insts.clearAndLeakNodesUnsafely();
 219   MBBNumbering.clear();
 220
 221   InstructionRecycler.clear(Allocator);
 222   OperandRecycler.clear(Allocator);
 223   BasicBlockRecycler.clear(Allocator);
 224   CodeViewAnnotations.clear();
 225   VariableDbgInfos.clear();
 226   if (RegInfo) {
 227     RegInfo->~MachineRegisterInfo();
 228     Allocator.Deallocate(RegInfo);
 229   }
 230   if (MFInfo) {
 231     MFInfo->~MachineFunctionInfo();
 232     Allocator.Deallocate(MFInfo);
 233   }
 234
 235   FrameInfo->~MachineFrameInfo();
 236   Allocator.Deallocate(FrameInfo);
 237
 238   ConstantPool->~MachineConstantPool();
 239   Allocator.Deallocate(ConstantPool);
 240
 241   if (JumpTableInfo) {
 242     JumpTableInfo->~MachineJumpTableInfo();
 243     Allocator.Deallocate(JumpTableInfo);
 244   }
 245
 246   if (WinEHInfo) {
 247     WinEHInfo->~WinEHFuncInfo();
 248     Allocator.Deallocate(WinEHInfo);
 249   }
 250
 251   if (WasmEHInfo) {
 252     WasmEHInfo->~WasmEHFuncInfo();
 253     Allocator.Deallocate(WasmEHInfo);
 254   }
 255 }
 256
 257 const DataLayout &MachineFunction::getDataLayout() const {
 258   return F.getParent()->getDataLayout();
 259 }
 260
 261 /// Get the JumpTableInfo for this function.
 262 /// If it does not already exist, allocate one.
 263 MachineJumpTableInfo *MachineFunction::
 264 getOrCreateJumpTableInfo(unsigned EntryKind) {
 265   if (JumpTableInfo) return JumpTableInfo;
 266
 267   JumpTableInfo = new (Allocator)
 268     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
 269   return JumpTableInfo;
 270 }
 271
 272 /// Should we be emitting segmented stack stuff for the function
 273 bool MachineFunction::shouldSplitStack() const {
 274   return getFunction().hasFnAttribute("split-stack");
 275 }
 276
 277 LLVM_NODISCARD unsigned
 278 MachineFunction::addFrameInst(const MCCFIInstruction &Inst) {
 279   FrameInstructions.push_back(Inst);
 280   return FrameInstructions.size() - 1;
 281 }
 282
 283 /// This discards all of the MachineBasicBlock numbers and recomputes them.
 284 /// This guarantees that the MBB numbers are sequential, dense, and match the
 285 /// ordering of the blocks within the function.  If a specific MachineBasicBlock
 286 /// is specified, only that block and those after it are renumbered.
 287 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
 288   if (empty()) { MBBNumbering.clear(); return; }
 289   MachineFunction::iterator MBBI, E = end();
 290   if (MBB == nullptr)
 291     MBBI = begin();
 292   else
 293     MBBI = MBB->getIterator();
 294
 295   // Figure out the block number this should have.
 296   unsigned BlockNo = 0;
 297   if (MBBI != begin())
 298     BlockNo = std::prev(MBBI)->getNumber() + 1;
 299
 300   for (; MBBI != E; ++MBBI, ++BlockNo) {
 301     if (MBBI->getNumber() != (int)BlockNo) {
 302       // Remove use of the old number.
 303       if (MBBI->getNumber() != -1) {
 304         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
 305                "MBB number mismatch!");
 306         MBBNumbering[MBBI->getNumber()] = nullptr;
 307       }
 308
 309       // If BlockNo is already taken, set that block's number to -1.
 310       if (MBBNumbering[BlockNo])
 311         MBBNumbering[BlockNo]->setNumber(-1);
 312
 313       MBBNumbering[BlockNo] = &*MBBI;
 314       MBBI->setNumber(BlockNo);
 315     }
 316   }
 317
 318   // Okay, all the blocks are renumbered.  If we have compactified the block
 319   // numbering, shrink MBBNumbering now.
 320   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
 321   MBBNumbering.resize(BlockNo);
 322 }
 323
 324 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 325 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
 326                                                   const DebugLoc &DL,
 327                                                   bool NoImp) {
 328   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 329     MachineInstr(*this, MCID, DL, NoImp);
 330 }
 331
 332 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,
 333 /// identical in all ways except the instruction has no parent, prev, or next.
 334 MachineInstr *
 335 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
 336   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
 337              MachineInstr(*this, *Orig);
 338 }
 339
 340 MachineInstr &MachineFunction::CloneMachineInstrBundle(MachineBasicBlock &MBB,
 341     MachineBasicBlock::iterator InsertBefore, const MachineInstr &Orig) {
 342   MachineInstr *FirstClone = nullptr;
 343   MachineBasicBlock::const_instr_iterator I = Orig.getIterator();
 344   while (true) {
 345     MachineInstr *Cloned = CloneMachineInstr(&*I);
 346     MBB.insert(InsertBefore, Cloned);
 347     if (FirstClone == nullptr) {
 348       FirstClone = Cloned;
 349     } else {
 350       Cloned->bundleWithPred();
 351     }
 352
 353     if (!I->isBundledWithSucc())
 354       break;
 355     ++I;
 356   }
 357   return *FirstClone;
 358 }
 359
 360 /// Delete the given MachineInstr.
 361 ///
 362 /// This function also serves as the MachineInstr destructor - the real
 363 /// ~MachineInstr() destructor must be empty.
 364 void
 365 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
 366   // Strip it for parts. The operand array and the MI object itself are
 367   // independently recyclable.
 368   if (MI->Operands)
 369     deallocateOperandArray(MI->CapOperands, MI->Operands);
 370   // Don't call ~MachineInstr() which must be trivial anyway because
 371   // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
 372   // destructors.
 373   InstructionRecycler.Deallocate(Allocator, MI);
 374 }
 375
 376 /// Allocate a new MachineBasicBlock. Use this instead of
 377 /// `new MachineBasicBlock'.
 378 MachineBasicBlock *
 379 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 380   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
 381              MachineBasicBlock(*this, bb);
 382 }
 383
 384 /// Delete the given MachineBasicBlock.
 385 void
 386 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
 387   assert(MBB->getParent() == this && "MBB parent mismatch!");
 388   MBB->~MachineBasicBlock();
 389   BasicBlockRecycler.Deallocate(Allocator, MBB);
 390 }
 391
 392 MachineMemOperand *MachineFunction::getMachineMemOperand(
 393     MachinePointerInfo PtrInfo, MachineMemOperand::Flags f, uint64_t s,
 394     unsigned base_alignment, const AAMDNodes &AAInfo, const MDNode *Ranges,
 395     SyncScope::ID SSID, AtomicOrdering Ordering,
 396     AtomicOrdering FailureOrdering) {
 397   return new (Allocator)
 398       MachineMemOperand(PtrInfo, f, s, base_alignment, AAInfo, Ranges,
 399                         SSID, Ordering, FailureOrdering);
 400 }
 401
 402 MachineMemOperand *
 403 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 404                                       int64_t Offset, uint64_t Size) {
 405   const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
 406
 407   // If there is no pointer value, the offset isn't tracked so we need to adjust
 408   // the base alignment.
 409   unsigned Align = PtrInfo.V.isNull()
 410                        ? MinAlign(MMO->getBaseAlignment(), Offset)
 411                        : MMO->getBaseAlignment();
 412
 413   return new (Allocator)
 414       MachineMemOperand(PtrInfo.getWithOffset(Offset), MMO->getFlags(), Size,
 415                         Align, AAMDNodes(), nullptr, MMO->getSyncScopeID(),
 416                         MMO->getOrdering(), MMO->getFailureOrdering());
 417 }
 418
 419 MachineMemOperand *
 420 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
 421                                       const AAMDNodes &AAInfo) {
 422   MachinePointerInfo MPI = MMO->getValue() ?
 423              MachinePointerInfo(MMO->getValue(), MMO->getOffset()) :
 424              MachinePointerInfo(MMO->getPseudoValue(), MMO->getOffset());
 425
 426   return new (Allocator)
 427              MachineMemOperand(MPI, MMO->getFlags(), MMO->getSize(),
 428                                MMO->getBaseAlignment(), AAInfo,
 429                                MMO->getRanges(), MMO->getSyncScopeID(),
 430                                MMO->getOrdering(), MMO->getFailureOrdering());
 431 }
 432
 433 MachineInstr::ExtraInfo *
 434 MachineFunction::createMIExtraInfo(ArrayRef<MachineMemOperand *> MMOs,
 435                                    MCSymbol *PreInstrSymbol,
 436                                    MCSymbol *PostInstrSymbol) {
 437   return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
 438                                          PostInstrSymbol);
 439 }
 440
 441 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
 442   char *Dest = Allocator.Allocate<char>(Name.size() + 1);
 443   llvm::copy(Name, Dest);
 444   Dest[Name.size()] = 0;
 445   return Dest;
 446 }
 447
 448 uint32_t *MachineFunction::allocateRegMask() {
 449   unsigned NumRegs = getSubtarget().getRegisterInfo()->getNumRegs();
 450   unsigned Size = MachineOperand::getRegMaskSize(NumRegs);
 451   uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 452   memset(Mask, 0, Size * sizeof(Mask[0]));
 453   return Mask;
 454 }
 455
 456 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 457 LLVM_DUMP_METHOD void MachineFunction::dump() const {
 458   print(dbgs());
 459 }
 460 #endif
 461
 462 StringRef MachineFunction::getName() const {
 463   return getFunction().getName();
 464 }
 465
 466 void MachineFunction::print(raw_ostream &OS, const SlotIndexes *Indexes) const {
 467   OS << "# Machine code for function " << getName() << ": ";
 468   getProperties().print(OS);
 469   OS << '\n';
 470
 471   // Print Frame Information
 472   FrameInfo->print(*this, OS);
 473
 474   // Print JumpTable Information
 475   if (JumpTableInfo)
 476     JumpTableInfo->print(OS);
 477
 478   // Print Constant Pool
 479   ConstantPool->print(OS);
 480
 481   const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
 482
 483   if (RegInfo && !RegInfo->livein_empty()) {
 484     OS << "Function Live Ins: ";
 485     for (MachineRegisterInfo::livein_iterator
 486          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
 487       OS << printReg(I->first, TRI);
 488       if (I->second)
 489         OS << " in " << printReg(I->second, TRI);
 490       if (std::next(I) != E)
 491         OS << ", ";
 492     }
 493     OS << '\n';
 494   }
 495
 496   ModuleSlotTracker MST(getFunction().getParent());
 497   MST.incorporateFunction(getFunction());
 498   for (const auto &BB : *this) {
 499     OS << '\n';
 500     // If we print the whole function, print it at its most verbose level.
 501     BB.print(OS, MST, Indexes, /*IsStandalone=*/true);
 502   }
 503
 504   OS << "\n# End machine code for function " << getName() << ".\n\n";
 505 }
 506
 507 namespace llvm {
 508
 509   template<>
 510   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
 511     DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 512
 513     static std::string getGraphName(const MachineFunction *F) {
 514       return ("CFG for '" + F->getName() + "' function").str();
 515     }
 516
 517     std::string getNodeLabel(const MachineBasicBlock *Node,
 518                              const MachineFunction *Graph) {
 519       std::string OutStr;
 520       {
 521         raw_string_ostream OSS(OutStr);
 522
 523         if (isSimple()) {
 524           OSS << printMBBReference(*Node);
 525           if (const BasicBlock *BB = Node->getBasicBlock())
 526             OSS << ": " << BB->getName();
 527         } else
 528           Node->print(OSS);
 529       }
 530
 531       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
 532
 533       // Process string output to make it nicer...
 534       for (unsigned i = 0; i != OutStr.length(); ++i)
 535         if (OutStr[i] == '\n') {                            // Left justify
 536           OutStr[i] = '\\';
 537           OutStr.insert(OutStr.begin()+i+1, 'l');
 538         }
 539       return OutStr;
 540     }
 541   };
 542
 543 } // end namespace llvm
 544
 545 void MachineFunction::viewCFG() const
 546 {
 547 #ifndef NDEBUG
 548   ViewGraph(this, "mf" + getName());
 549 #else
 550   errs() << "MachineFunction::viewCFG is only available in debug builds on "
 551          << "systems with Graphviz or gv!\n";
 552 #endif // NDEBUG
 553 }
 554
 555 void MachineFunction::viewCFGOnly() const
 556 {
 557 #ifndef NDEBUG
 558   ViewGraph(this, "mf" + getName(), true);
 559 #else
 560   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
 561          << "systems with Graphviz or gv!\n";
 562 #endif // NDEBUG
 563 }
 564
 565 /// Add the specified physical register as a live-in value and
 566 /// create a corresponding virtual register for it.
 567 unsigned MachineFunction::addLiveIn(unsigned PReg,
 568                                     const TargetRegisterClass *RC) {
 569   MachineRegisterInfo &MRI = getRegInfo();
 570   unsigned VReg = MRI.getLiveInVirtReg(PReg);
 571   if (VReg) {
 572     const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
 573     (void)VRegRC;
 574     // A physical register can be added several times.
 575     // Between two calls, the register class of the related virtual register
 576     // may have been constrained to match some operation constraints.
 577     // In that case, check that the current register class includes the
 578     // physical register and is a sub class of the specified RC.
 579     assert((VRegRC == RC || (VRegRC->contains(PReg) &&
 580                              RC->hasSubClassEq(VRegRC))) &&
 581             "Register class mismatch!");
 582     return VReg;
 583   }
 584   VReg = MRI.createVirtualRegister(RC);
 585   MRI.addLiveIn(PReg, VReg);
 586   return VReg;
 587 }
 588
 589 /// Return the MCSymbol for the specified non-empty jump table.
 590 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 591 /// normal 'L' label is returned.
 592 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
 593                                         bool isLinkerPrivate) const {
 594   const DataLayout &DL = getDataLayout();
 595   assert(JumpTableInfo && "No jump tables");
 596   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
 597
 598   StringRef Prefix = isLinkerPrivate ? DL.getLinkerPrivateGlobalPrefix()
 599                                      : DL.getPrivateGlobalPrefix();
 600   SmallString<60> Name;
 601   raw_svector_ostream(Name)
 602     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
 603   return Ctx.getOrCreateSymbol(Name);
 604 }
 605
 606 /// Return a function-local symbol to represent the PIC base.
 607 MCSymbol *MachineFunction::getPICBaseSymbol() const {
 608   const DataLayout &DL = getDataLayout();
 609   return Ctx.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
 610                                Twine(getFunctionNumber()) + "$pb");
 611 }
 612
 613 /// \name Exception Handling
 614 /// \{
 615
 616 LandingPadInfo &
 617 MachineFunction::getOrCreateLandingPadInfo(MachineBasicBlock *LandingPad) {
 618   unsigned N = LandingPads.size();
 619   for (unsigned i = 0; i < N; ++i) {
 620     LandingPadInfo &LP = LandingPads[i];
 621     if (LP.LandingPadBlock == LandingPad)
 622       return LP;
 623   }
 624
 625   LandingPads.push_back(LandingPadInfo(LandingPad));
 626   return LandingPads[N];
 627 }
 628
 629 void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
 630                                 MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 631   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 632   LP.BeginLabels.push_back(BeginLabel);
 633   LP.EndLabels.push_back(EndLabel);
 634 }
 635
 636 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
 637   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
 638   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 639   LP.LandingPadLabel = LandingPadLabel;
 640
 641   const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
 642   if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
 643     if (const auto *PF =
 644             dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
 645       getMMI().addPersonality(PF);
 646
 647     if (LPI->isCleanup())
 648       addCleanup(LandingPad);
 649
 650     // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
 651     //        correct, but we need to do it this way because of how the DWARF EH
 652     //        emitter processes the clauses.
 653     for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
 654       Value *Val = LPI->getClause(I - 1);
 655       if (LPI->isCatch(I - 1)) {
 656         addCatchTypeInfo(LandingPad,
 657                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
 658       } else {
 659         // Add filters in a list.
 660         auto *CVal = cast<Constant>(Val);
 661         SmallVector<const GlobalValue *, 4> FilterList;
 662         for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
 663              II != IE; ++II)
 664           FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
 665
 666         addFilterTypeInfo(LandingPad, FilterList);
 667       }
 668     }
 669
 670   } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
 671     for (unsigned I = CPI->getNumArgOperands(); I != 0; --I) {
 672       Value *TypeInfo = CPI->getArgOperand(I - 1)->stripPointerCasts();
 673       addCatchTypeInfo(LandingPad, dyn_cast<GlobalValue>(TypeInfo));
 674     }
 675
 676   } else {
 677     assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
 678   }
 679
 680   return LandingPadLabel;
 681 }
 682
 683 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 684                                        ArrayRef<const GlobalValue *> TyInfo) {
 685   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 686   for (unsigned N = TyInfo.size(); N; --N)
 687     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 688 }
 689
 690 void MachineFunction::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 691                                         ArrayRef<const GlobalValue *> TyInfo) {
 692   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 693   std::vector<unsigned> IdsInFilter(TyInfo.size());
 694   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 695     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 696   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 697 }
 698
 699 void MachineFunction::tidyLandingPads(DenseMap<MCSymbol *, uintptr_t> *LPMap,
 700                                       bool TidyIfNoBeginLabels) {
 701   for (unsigned i = 0; i != LandingPads.size(); ) {
 702     LandingPadInfo &LandingPad = LandingPads[i];
 703     if (LandingPad.LandingPadLabel &&
 704         !LandingPad.LandingPadLabel->isDefined() &&
 705         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 706       LandingPad.LandingPadLabel = nullptr;
 707
 708     // Special case: we *should* emit LPs with null LP MBB. This indicates
 709     // "nounwind" case.
 710     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 711       LandingPads.erase(LandingPads.begin() + i);
 712       continue;
 713     }
 714
 715     if (TidyIfNoBeginLabels) {
 716       for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 717         MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 718         MCSymbol *EndLabel = LandingPad.EndLabels[j];
 719         if ((BeginLabel->isDefined() || (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 720             (EndLabel->isDefined() || (LPMap && (*LPMap)[EndLabel] != 0)))
 721           continue;
 722
 723         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 724         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 725         --j;
 726         --e;
 727       }
 728
 729       // Remove landing pads with no try-ranges.
 730       if (LandingPads[i].BeginLabels.empty()) {
 731         LandingPads.erase(LandingPads.begin() + i);
 732         continue;
 733       }
 734     }
 735
 736     // If there is no landing pad, ensure that the list of typeids is empty.
 737     // If the only typeid is a cleanup, this is the same as having no typeids.
 738     if (!LandingPad.LandingPadBlock ||
 739         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 740       LandingPad.TypeIds.clear();
 741     ++i;
 742   }
 743 }
 744
 745 void MachineFunction::addCleanup(MachineBasicBlock *LandingPad) {
 746   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 747   LP.TypeIds.push_back(0);
 748 }
 749
 750 void MachineFunction::addSEHCatchHandler(MachineBasicBlock *LandingPad,
 751                                          const Function *Filter,
 752                                          const BlockAddress *RecoverBA) {
 753   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 754   SEHHandler Handler;
 755   Handler.FilterOrFinally = Filter;
 756   Handler.RecoverBA = RecoverBA;
 757   LP.SEHHandlers.push_back(Handler);
 758 }
 759
 760 void MachineFunction::addSEHCleanupHandler(MachineBasicBlock *LandingPad,
 761                                            const Function *Cleanup) {
 762   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 763   SEHHandler Handler;
 764   Handler.FilterOrFinally = Cleanup;
 765   Handler.RecoverBA = nullptr;
 766   LP.SEHHandlers.push_back(Handler);
 767 }
 768
 769 void MachineFunction::setCallSiteLandingPad(MCSymbol *Sym,
 770                                             ArrayRef<unsigned> Sites) {
 771   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
 772 }
 773
 774 unsigned MachineFunction::getTypeIDFor(const GlobalValue *TI) {
 775   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 776     if (TypeInfos[i] == TI) return i + 1;
 777
 778   TypeInfos.push_back(TI);
 779   return TypeInfos.size();
 780 }
 781
 782 int MachineFunction::getFilterIDFor(std::vector<unsigned> &TyIds) {
 783   // If the new filter coincides with the tail of an existing filter, then
 784   // re-use the existing filter.  Folding filters more than this requires
 785   // re-ordering filters and/or their elements - probably not worth it.
 786   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 787        E = FilterEnds.end(); I != E; ++I) {
 788     unsigned i = *I, j = TyIds.size();
 789
 790     while (i && j)
 791       if (FilterIds[--i] != TyIds[--j])
 792         goto try_next;
 793
 794     if (!j)
 795       // The new filter coincides with range [i, end) of the existing filter.
 796       return -(1 + i);
 797
 798 try_next:;
 799   }
 800
 801   // Add the new filter.
 802   int FilterID = -(1 + FilterIds.size());
 803   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 804   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
 805   FilterEnds.push_back(FilterIds.size());
 806   FilterIds.push_back(0); // terminator
 807   return FilterID;
 808 }
 809
 810 void MachineFunction::addCodeViewHeapAllocSite(MachineInstr *I, MDNode *MD) {
 811   MCSymbol *BeginLabel = Ctx.createTempSymbol("heapallocsite", true);
 812   MCSymbol *EndLabel = Ctx.createTempSymbol("heapallocsite", true);
 813   I->setPreInstrSymbol(*this, BeginLabel);
 814   I->setPostInstrSymbol(*this, EndLabel);
 815
 816   DIType *DI = dyn_cast<DIType>(MD);
 817   CodeViewHeapAllocSites.push_back(std::make_tuple(BeginLabel, EndLabel, DI));
 818 }
 819
 820 /// \}
 821
 822 //===----------------------------------------------------------------------===//
 823 //  MachineJumpTableInfo implementation
 824 //===----------------------------------------------------------------------===//
 825
 826 /// Return the size of each entry in the jump table.
 827 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
 828   // The size of a jump table entry is 4 bytes unless the entry is just the
 829   // address of a block, in which case it is the pointer size.
 830   switch (getEntryKind()) {
 831   case MachineJumpTableInfo::EK_BlockAddress:
 832     return TD.getPointerSize();
 833   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 834     return 8;
 835   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 836   case MachineJumpTableInfo::EK_LabelDifference32:
 837   case MachineJumpTableInfo::EK_Custom32:
 838     return 4;
 839   case MachineJumpTableInfo::EK_Inline:
 840     return 0;
 841   }
 842   llvm_unreachable("Unknown jump table encoding!");
 843 }
 844
 845 /// Return the alignment of each entry in the jump table.
 846 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
 847   // The alignment of a jump table entry is the alignment of int32 unless the
 848   // entry is just the address of a block, in which case it is the pointer
 849   // alignment.
 850   switch (getEntryKind()) {
 851   case MachineJumpTableInfo::EK_BlockAddress:
 852     return TD.getPointerABIAlignment(0);
 853   case MachineJumpTableInfo::EK_GPRel64BlockAddress:
 854     return TD.getABIIntegerTypeAlignment(64);
 855   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
 856   case MachineJumpTableInfo::EK_LabelDifference32:
 857   case MachineJumpTableInfo::EK_Custom32:
 858     return TD.getABIIntegerTypeAlignment(32);
 859   case MachineJumpTableInfo::EK_Inline:
 860     return 1;
 861   }
 862   llvm_unreachable("Unknown jump table encoding!");
 863 }
 864
 865 /// Create a new jump table entry in the jump table info.
 866 unsigned MachineJumpTableInfo::createJumpTableIndex(
 867                                const std::vector<MachineBasicBlock*> &DestBBs) {
 868   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
 869   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
 870   return JumpTables.size()-1;
 871 }
 872
 873 /// If Old is the target of any jump tables, update the jump tables to branch
 874 /// to New instead.
 875 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
 876                                                   MachineBasicBlock *New) {
 877   assert(Old != New && "Not making a change?");
 878   bool MadeChange = false;
 879   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
 880     ReplaceMBBInJumpTable(i, Old, New);
 881   return MadeChange;
 882 }
 883
 884 /// If Old is a target of the jump tables, update the jump table to branch to
 885 /// New instead.
 886 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
 887                                                  MachineBasicBlock *Old,
 888                                                  MachineBasicBlock *New) {
 889   assert(Old != New && "Not making a change?");
 890   bool MadeChange = false;
 891   MachineJumpTableEntry &JTE = JumpTables[Idx];
 892   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
 893     if (JTE.MBBs[j] == Old) {
 894       JTE.MBBs[j] = New;
 895       MadeChange = true;
 896     }
 897   return MadeChange;
 898 }
 899
 900 void MachineJumpTableInfo::print(raw_ostream &OS) const {
 901   if (JumpTables.empty()) return;
 902
 903   OS << "Jump Tables:\n";
 904
 905   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
 906     OS << printJumpTableEntryReference(i) << ": ";
 907     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
 908       OS << ' ' << printMBBReference(*JumpTables[i].MBBs[j]);
 909   }
 910
 911   OS << '\n';
 912 }
 913
 914 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 915 LLVM_DUMP_METHOD void MachineJumpTableInfo::dump() const { print(dbgs()); }
 916 #endif
 917
 918 Printable llvm::printJumpTableEntryReference(unsigned Idx) {
 919   return Printable([Idx](raw_ostream &OS) { OS << "%jump-table." << Idx; });
 920 }
 921
 922 //===----------------------------------------------------------------------===//
 923 //  MachineConstantPool implementation
 924 //===----------------------------------------------------------------------===//
 925
 926 void MachineConstantPoolValue::anchor() {}
 927
 928 Type *MachineConstantPoolEntry::getType() const {
 929   if (isMachineConstantPoolEntry())
 930     return Val.MachineCPVal->getType();
 931   return Val.ConstVal->getType();
 932 }
 933
 934 bool MachineConstantPoolEntry::needsRelocation() const {
 935   if (isMachineConstantPoolEntry())
 936     return true;
 937   return Val.ConstVal->needsRelocation();
 938 }
 939
 940 SectionKind
 941 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
 942   if (needsRelocation())
 943     return SectionKind::getReadOnlyWithRel();
 944   switch (DL->getTypeAllocSize(getType())) {
 945   case 4:
 946     return SectionKind::getMergeableConst4();
 947   case 8:
 948     return SectionKind::getMergeableConst8();
 949   case 16:
 950     return SectionKind::getMergeableConst16();
 951   case 32:
 952     return SectionKind::getMergeableConst32();
 953   default:
 954     return SectionKind::getReadOnly();
 955   }
 956 }
 957
 958 MachineConstantPool::~MachineConstantPool() {
 959   // A constant may be a member of both Constants and MachineCPVsSharingEntries,
 960   // so keep track of which we've deleted to avoid double deletions.
 961   DenseSet<MachineConstantPoolValue*> Deleted;
 962   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
 963     if (Constants[i].isMachineConstantPoolEntry()) {
 964       Deleted.insert(Constants[i].Val.MachineCPVal);
 965       delete Constants[i].Val.MachineCPVal;
 966     }
 967   for (DenseSet<MachineConstantPoolValue*>::iterator I =
 968        MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
 969        I != E; ++I) {
 970     if (Deleted.count(*I) == 0)
 971       delete *I;
 972   }
 973 }
 974
 975 /// Test whether the given two constants can be allocated the same constant pool
 976 /// entry.
 977 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
 978                                       const DataLayout &DL) {
 979   // Handle the trivial case quickly.
 980   if (A == B) return true;
 981
 982   // If they have the same type but weren't the same constant, quickly
 983   // reject them.
 984   if (A->getType() == B->getType()) return false;
 985
 986   // We can't handle structs or arrays.
 987   if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
 988       isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
 989     return false;
 990
 991   // For now, only support constants with the same size.
 992   uint64_t StoreSize = DL.getTypeStoreSize(A->getType());
 993   if (StoreSize != DL.getTypeStoreSize(B->getType()) || StoreSize > 128)
 994     return false;
 995
 996   Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
 997
 998   // Try constant folding a bitcast of both instructions to an integer.  If we
 999   // get two identical ConstantInt's, then we are good to share them.  We use
1000   // the constant folding APIs to do this so that we get the benefit of
1001   // DataLayout.
1002   if (isa<PointerType>(A->getType()))
1003     A = ConstantFoldCastOperand(Instruction::PtrToInt,
1004                                 const_cast<Constant *>(A), IntTy, DL);
1005   else if (A->getType() != IntTy)
1006     A = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(A),
1007                                 IntTy, DL);
1008   if (isa<PointerType>(B->getType()))
1009     B = ConstantFoldCastOperand(Instruction::PtrToInt,
1010                                 const_cast<Constant *>(B), IntTy, DL);
1011   else if (B->getType() != IntTy)
1012     B = ConstantFoldCastOperand(Instruction::BitCast, const_cast<Constant *>(B),
1013                                 IntTy, DL);
1014
1015   return A == B;
1016 }
1017
1018 /// Create a new entry in the constant pool or return an existing one.
1019 /// User must specify the log2 of the minimum required alignment for the object.
1020 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
1021                                                    unsigned Alignment) {
1022   assert(Alignment && "Alignment must be specified!");
1023   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1024
1025   // Check to see if we already have this constant.
1026   //
1027   // FIXME, this could be made much more efficient for large constant pools.
1028   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
1029     if (!Constants[i].isMachineConstantPoolEntry() &&
1030         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, DL)) {
1031       if ((unsigned)Constants[i].getAlignment() < Alignment)
1032         Constants[i].Alignment = Alignment;
1033       return i;
1034     }
1035
1036   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
1037   return Constants.size()-1;
1038 }
1039
1040 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
1041                                                    unsigned Alignment) {
1042   assert(Alignment && "Alignment must be specified!");
1043   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
1044
1045   // Check to see if we already have this constant.
1046   //
1047   // FIXME, this could be made much more efficient for large constant pools.
1048   int Idx = V->getExistingMachineCPValue(this, Alignment);
1049   if (Idx != -1) {
1050     MachineCPVsSharingEntries.insert(V);
1051     return (unsigned)Idx;
1052   }
1053
1054   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
1055   return Constants.size()-1;
1056 }
1057
1058 void MachineConstantPool::print(raw_ostream &OS) const {
1059   if (Constants.empty()) return;
1060
1061   OS << "Constant Pool:\n";
1062   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
1063     OS << "  cp#" << i << ": ";
1064     if (Constants[i].isMachineConstantPoolEntry())
1065       Constants[i].Val.MachineCPVal->print(OS);
1066     else
1067       Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
1068     OS << ", align=" << Constants[i].getAlignment();
1069     OS << "\n";
1070   }
1071 }
1072
1073 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1074 LLVM_DUMP_METHOD void MachineConstantPool::dump() const { print(dbgs()); }
1075 #endif